Unexplored Space More Interesting Than the North Pole

Above there extends a vast unexplored space far more interesting from a scientific point of view than the icy regions around the north pole. No one can reach the limit of the upper regions of the air and live, unless he carries with him air to breathe and fuel to warm him, for at the paltry distance of ten miles above the earth the air is too thin to support respiration, and the thermometer would register far below zero. It would be a region of perpetual snow on a peak of the earth if it should rise to such a height. A person in a balloon could not hear a friend in a neighboring balloon, even if they were near enough to shake hands. There would be no medium for the propagation of sound waves. There would, however, still be a medium for the conduction of electricity — a medium in fact of great conductibility — almost as good as a metal, and it is this medium at even a less height which Tesla proposes to use in his methods of transmitting power hundreds of miles through the air without wires.

We live under a blanket of air which protects us from the extreme cold of outer space. This low temperature becomes evident fourteen or fifteen thousand feet above the surface of the earth, and would, as I have said, reach a point far below zero at a height of ten miles. At this height we should no longer observe the twinkling of the stars, for this scintiliation is due to the movements of our atmosphere, which at the height I have mentioned would be extremely rarified. If one could photograph the sun's spectrum at this altitude we could greatly extend our knowledge of the shortest wave lengths of light; for the atmosphere completely absorbs such wave lengths as are concerned in the X-ray phenomena. That this absorption really takes place can be proved in a laboratory.

The heat and light which we receive from the sun are greatly modified by this blanketing layer of air. The long waves of the energy from the sun аге called heat waves. The intermediate waves are termed light waves, and we receive these in full measure. The very short, waves, however, are stopped by our atmosphere and are transformed into — what?